Heterogeneous RDF Databases

Querying generic triple stores are inefficient as they do not gather all the properties of an entity together. This forces a self join for each additional attribute involved in the query. Migrating to a conventional relation provides the efficiency we are used to, and the brittleness we are used to enduring. The goal of the heterogeneous rdf databases is to provide an optimizable compromose between the two.

The SQL query generator parses an RDF query and examines the predicates to determine whether they will come from a conventional relation or, if the data in question isn't in any of those schemas, from a generic triple store. This allows the custodian of the data to migrate data between the triple store and entity-specific relations (henceforth ESRs) to optimize for efficiency or clarity. The data in ESRs can be accessed by conventional non-RDF tools. One likely consumer of this technology is the digital libraries community.

The sales department has used the _Statements_ table to add information without changing the deployed schema for either Customers or Orders. Further, this data is not just in notes, but is actually linked to the other elements in the database by more than coincident sounding strings (see actual _Statements_ implementation below for how). Then can then query for optional additional marketing information when selling pool supplied with